Call of Duty 4: Modern Warfare is a first person shooter game for the PC, Playstation 3, Xbox 360, and Nintendo DS. All four platforms have multiplayer capability but only the PC, PS3 and Xbox 360 have the ability to play the game online.

Once you have it installed, to play Call of Duty: Modern Warfare offline, all you need to do is select the Go Offline option. This will let you boot up the campaign and get cracking with the story, simple as you like.

In a 2-by-2 table with cells a, b, c, and d (see figure), the odds ratio is odds of the event in the exposure group (a/b) divided by the odds of the event in the control or non-exposure group (c/d). Thus the odds ratio is (a/b) / (c/d) which simplifies to ad/bc.

Calculating probabilities is expressed as a percent and follows the formula: Probability = Favorable cases / possible cases x 100.